Digital Techno Bytes

Reliability Centred Maintenance (RCM) the future of Proactive Maintenance Management

In the last couple of years there has been a clamour for Prescriptive and Predictive Maintenance to move away from traditional Time Based Maintenance to Condition Based Maintenance especially in Asset heavy Industry Verticals of Oil & Gas, Petrochemicals , Power and Metal Mines Minerals. For sometime now Industry experts have been advocating use of Data Driven technology combined with Advance Analytics to gain insights into Asset behaviour its diagnostics vide data that gets captured in Process Systems and other systems like Vibration Monitoring Systems and use it for decision making.

Typically analytics is used for smart notifications and alerts to give a window of opportunity to the Operations and Maintenance Team to pre-empt anomalies in advance in any asset condition before it turns into a catastrophe. But how you consume these Early Warning Notifications / Alerts sets the tone for Proactive Maintenance Management.

This is where Reliability Centred Maintenance (RCM) comes into picture. Reliability Centered Maintenance (RCM) is a concept of maintenance planning to ensure that systems continue to do what their user require in their present operating context. Successful implementation of RCM will lead to increase in cost effectiveness, reliability, machine uptime, and a greater understanding of the level of risk that the organization is managing.Ultimately, by performing RCM, organizations are looking to develop unique maintenance schedules for each critical asset within a facility or organization.

There are four basic principles of an RCM program, stated in different ways by organizations all over the world. A program is RCM if it:

1) Is designed ,scoped and structured to preserve system function
2) Identifies failure modes, which are the ways in which something might fail. Failures are any errors or defects, especially ones that affect the customer, and can be potential or actual
3) Addresses failure modes by importance
4) Defines applicable maintenance task candidates and selects the most effective one in the case of important failure modes

Industry Experts / Domain Consultants have described an RCM program as:

• A process that “uses a cross-functional team to develop a complete maintenance strategy designed to ensure inherent design reliability for a process or piece of equipment.”
• A way “to identify components whose functional failures can cause unwanted consequences to one’s plant or facility.”

As per the technical standard SAE JA1011, Evaluation Criteria for RCM Processes, which sets out the minimum criteria that any process should meet before it can be called RCM. This starts with the seven questions below, worked through in the order that they are listed:

1. What is the item supposed to do and its associated performance standards?

2. In what ways can it fail to provide the required functions?

3. What are the events that cause each failure?

4. What happens when each failure occurs?

5. In what way does each failure matter?

6. What systematic task can be performed proactively to prevent, or to diminish to a satisfactory degree, the consequences of the failure?

7. What must be done if a suitable preventive task cannot be found?

Reliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regimen. It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context. As a discipline it enables machinery stakeholders to monitor, assess, predict and generally understand the working of their physical assets. This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery, and write a Failure Mode Effects and Criticality Analysis (FMECA). The second part of the analysis is to apply the "RCM logic", which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA. Once the logic is complete for all elements in the FMECA, the resulting list of maintenance is "packaged", so that the periodicities of the tasks are rationalised to be called up in work packages; it is important not to destroy the applicability of maintenance in this phase. Lastly, RCM is kept live throughout the "in-service" life of machinery, where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained.

RCM can be used to create a cost-effective maintenance strategy to address dominant causes of equipment failure. It is a systematic approach to defining a routine maintenance program composed of cost-effective tasks that preserve important functions.

The important functions (of a piece of equipment) to preserve with routine maintenance are identified, their dominant failure modes and causes determined and the consequences of failure ascertained. Levels of criticality are assigned to the consequences of failure. Some functions are not critical and are left to "run to failure" while other functions mustbe preserved at all cost. Maintenance tasks are selected that address the dominant failure causes. This process directly addresses maintenance preventable failures. Failures caused by unlikely events, non-predictable acts of nature, etc. will usually receive no action provided their risk (combination of severity and frequency) is trivial (or at least tolerable). When the risk of such failures is very high, RCM encourages (and sometimes mandates) the user to consider changing something which will reduce the risk to a tolerable level.

The result is a maintenance program that focuses scarce economic resources on those items that would cause the most disruption if they were to fail.

RCM emphasizes the use of predictive maintenance (PdM) techniques in addition to traditional preventive measures.

How Do You Implement A Reliability Centered Maintenance Program?

There are three phases (Decision, Analysis and Act) of a reliability centered maintenance program , and seven steps within these phases to ensure the program is fully implemented.

 

Phase I: Decision

Justification and planning based on need, readiness and desired outcomes.

1. Analysis Preparation
RCM analysis is only as effective as the team behind it. The most effective cross-functional teams include maintenance employees, project leaders, subject matter experts, and if possible, executive leadership.

Additionally, documenting procedures and your project plan can be vital to keeping your team on track. The beginning of an RCM project is a great time to outline your organizational goals, project management concerns, budget and timeline, and potential obstacles.

2. Select Equipment for RCM Analysis
Equipment selected for RCM analysis should be critical to operations, the cost of repair vs. replace and previous spending on Preventive Maintenance. To select the best candidate, ask yourself these questions:

• Could failure be difficult to detect during normal operation and maintenance?
• Could failure affect safety?
• Could failure have a significant impact on operations?
• Could failure have a significant impact on spending?

3. Identify Functionality 
Define a complete list of a piece of equipment’s functionality, including as much data driven information as possible. It is important for your team to specify your desired asset performance levels instead of actual performance, as it may reflect an operational or maintenance issue. System functionality then drives the required functions of the equipment supporting the system functions.

 

Phase II: Analysis

Conduct the RCM study in a way that provides a high quality output.

4. Identify Functional Failures
Functional failure is the inability of an asset or system to meet acceptable standards of performance. Failures can encompass poor performance, over performance, performing unnecessary or unintended functions, or complete failure.

 For example, when a motor bearing is failing due to lack of lubrication, a Total Functional Failure would be the motor not rotating, and the motor failing to function.

The below table presents the statistics for RCM System analysis profile. This profile contains information that is very descriptive with the details the team has examined & discussed. Here and some typical observations

5. Identify and Evaluate the Effects of Failures
Next, your team should document what actually happens when failures occur. What can be observed? What is the impact of the failure on production? Is there a significant safety impact?

6. Identify Failure Modes 
Once you identify your equipment and systematic functional failures, failure modes must be considered. One of the most common techniques to approach discovering failure modes is Failure mode and effects analysis (FMEA). FMEA is a step-by-step approach for identifying all possible failures in a design, a manufacturing or assembly process, or a product or service. Understanding the effects of failure involves asking questions such as:

• What are the safety concerns with this failure?

• What impact does this failure have on operation/production?

• Does this failure mode result in full or partial outages?

A CMMS offers automation tools to help reduce missing scheduled work and equipment failures, making PM optimization as efficient and streamlined as possible. PM Task Generation, PM Scheduling and Inspections help facilitate continuous improvement and support for an organization’s Preventive Maintenance program.

Phase III: Act

Act on the study’s recommendations to update asset and maintenance systems, procedures and design improvements.

7. Select Maintenance Tasks
At this point, the most appropriate maintenance action can be identified based on the failure mode information. Failure management techniques can be grouped into two categories:

• Proactive tasks – Preventive and Predictive Maintenance techniques are performed to prevent failure of a piece of equipment of system. Preventive Maintenance is calendar or usage based, and helps to reduce the risk of failure, while Predictive Maintenance, or Condition Monitoring, can detect the failure before it begins.
• Default actions – Fire fighting or reactive maintenance deal with failures after the fact. Run-to-failure is a tactic where equipment is run until it fails, and then work is performed.

Selecting the right strategy for failure management is rooted in an understanding of failure modes, criticality of equipment and the economic impact of failure.

RCM implementation with a CMMS

A properly implemented Computerized Maintenance Management System (CMMS) can support the RCM process. CMMS helps maintenance programs develop goals for cost tracking, benchmark data and monitor the bottom line. For example, with proper Online reporting and dashboard tools, organizations can consistently document work order history, failures, costs and trends. With a few clicks of a mouse, organizations have access to the data to perform the analyses that RCM requires.

The goals of RCM include the ability to evaluate, categorize, prioritize and understand the appropriate way to intervene in the impact of failures. Ultimately, by performing RCM, an organization is looking to develop unique maintenance schedules for each critical asset within a facility or organization.

Successful implementation of a RCM process, coupled with CMMS software, will increase cost effectiveness, asset reliability, equipment uptime, and an enhanced understanding of the level of risk that the organization is managing.

If you go by popular sentiments then if Preventive Maintenance and Predictive maintenance is the need of the hour in achieving Operational Excellence but Reliability Centered Maintenance (RCM) is the future of Proactive Maintenance Management.